1. Field of the Invention
This invention relates to a vehicle safety air bag device having a folded air bag which is inflated and expands in a vehicle interior so as to protect an occupant of the vehicle against injuries during front-end collisions. Additionally, the present invention relates to a particular method of folding the air bag used in such a device.
2. Description of Related Art
In recent years, safety air bags have been installed in vehicles in order to protect occupants of the vehicles, such as a driver and a passenger seated in front seats, against injuries during a collision. For protecting an occupant of the front passenger seat, the safety air bag is typically installed behind a dashboard in front of the passenger seat of the vehicle. An inflater or gas generator generates a pressurized inert gas, and inflates and expands the air bag in the vehicle interior or compartment so as to act as a cushion on the occupant.
It is important to complete inflation and expansion of an air bag rapidly so as to provide sufficiently swift contact between the air bag and the occupant during a collision in order for the occupant to be positively restricted from moving by the inflated air bag.
Because occupants of a front passenger seat move around and vary their postures much more often than occupants of a front driver seat, a passenger seat side air bag is designed to have an inflated volume or size which is almost three times as large as the inflated volume or size of a driver seat side air bag. Therefore, a passenger seat side air bag needs a longer inflation time than does the driver seat side air bag. For this reason, an occupant of the passenger seat will often be contacted by an expanding air bag at a later time than that at which an occupant of the driver seat is contacted by the driver seat side air bag.
In order for the passenger seat side air bag to be rapidly inflated and expanded in a short time, it is possible to increase pressure of the gas supplied into the air bag. However, providing a gas under increased pressure causes the passenger seat side air bag to apply a great impact against the occupant of the front passenger seat.